Killing skeletons (unless you use a spawner) is a very crappy way to get arrows. Kill chickens and zombies any chance you get for their feathers. Get 20 gravel, build a pillar, and shovel it down, build it, and shovel it, etc. Each time you have a chance to get flint. --- Gamertag: Archlvt 3DS FC: 4296 3610 2207
In order to get arrows you should probably kill skeletons. The mob trap idea is that if you find a dungeon that has a mob spawner inside of it that is spawning skeletons, you can create a trap so that when the skeletons spawn they die and you can collect their stuff. It takes time and luck to find a spawner though. To mine you should be at the level 13 or bellow (13 counting from bedrock up). Then mine in a straight line however many blocks you want, then go back to where you started and mine in another straight line but this line is 3 blocks away from the original line. It should look like this:
L SS L SS L SS L L SS L SS L SS L L SS L SS L SS L
L=Line S=Stone (or any other block) This makes it so you can see both sides of the wall without having to do any extra work.